The preparative and data management core will provide red cell density separation and analysis, HPLC (high performance liquid chromatography) analysis and molecular biology support to the program grant. A number of preparative and analytic procedures are used by most members of the center projects. Some of these procedures (density gradient analysis using Percoll-Larex continuous density gradients) were originated in this laboratory and have proved invaluable in sorting out the consequences of the intercellular heterogeneity which is characteristic of the sickle cell syndromes (1-4). The procedures require a portion of a technician who is experienced in preparing the needed solutions (density gradient mixes, HPLC solvents, etc.), performing the analysis in question, and then entering the values into the laboratory data base for use by all investigators. The core will also provide advice and assistance in preparing samples for scanning and transmission electron microscopy. Expenses for materials used and service contracts for the instruments currently utilized are substantial and need to be shared among the projects. Red cell density separation and analysis is used in Projects two, three, six and seven. HPLC will be used in projects one, three and six to characterize the globin chains present in human and mouse red cells. The need for molecular biology support is self explanatory in projects three and six.